Nitti is the oldest of Al Capone's lieutenants. He comes into the Torrio/Capone gang during Prohibition as a whiskey smuggler, and within a few years, he works his way up to one of Capone's top advisors. His tax evasion conviction tips Capone off to just how in-depth the Treasury Department's investigations are into his gang. While Nitti is away, he discovers his intense claustrophobia. And when his Hollywood extortion racket gets busted, rather than go back to jail, he takes his own life.